Applicable to: C.3 Motorized Emptying and Transport Systems 1, 4-7, 9 Application Level: Management Level: Inputs/Outputs: Sludge Blackwater Household Household Effluent Urine Stored Urine Neighbourhood Shared C3: MOCityTORIZED EMPTYING Public AND TRANSPORT sludge Motorized emptying and transport refers to a vehi- ed areas have capacities of 500 to 800 L. These vehicles cle equipped with a motorized pump and a storage use, for example, two-wheel tractor or motorcycle based tank for emptying and transporting faecal sludge drives and can reach speeds of up to 12 km/h. and urine. Humans are required to operate the Pumps can usually only suck down to a depth of 2 to 3 pump and manoeuvre the hose, but sludge is not m (depending on the strength of the pump) and must be manually lifted or transported. located within 30 m of the pit. In general, the closer the vacuum pump can be to the pit, the easier it is to empty. A truck is fitted with a pump which is connected to a hose that is lowered down into a tank (e.g., Septic Tank, Appropriateness Depending on the Collection and S.9) or pit, and the sludge is pumped up into the holding Storage technology, the sludge can be so dense that it tank on the vehicle. This type of design is often referred cannot be easily pumped. In these situations it is neces- to as a vacuum truck. sary to thin the solids with water so that they flow more Alternative motorized vehicles or machines have been easily, but this may be inefficient and costly. Garbage developed for densely populated areas with limited and sand make emptying much more difficult and clog access. Designs such as the Vacutug, Dung Beetle, Mol- the pipe or pump. Multiple truckloads may be required sta or Kedoteng carry a small sludge tank and a pump for large Septic Tanks. and can negotiate narrow pathways. Although large vacuum trucks cannot access areas with narrow or non-driveable roads, they remain the norm Design Considerations Generally, the storage for municipalities and sanitation authorities. These capacity of a vacuum truck is between 3 and 12 m3. Local trucks can rarely make trips to remote areas (e.g., in trucks are commonly adapted for sludge transport by the periphery of a city) since the income generated may equipping them with holding tanks and pumps. Modified not offset the cost of fuel and time. Therefore, the treat- pick-ups and tractor trailers can transport around 1.5 m3, ment site must be within reach from the serviced areas. but capacities vary. Smaller vehicles for densely populat- Transfer Stations (C.7) and adequate treatment are also Compendium of Sanitation Systems and Technologies Compendium of Sanitation Systems and Conveyance C: Functional Group 88 C.3 crucial for service providers using small-scale motorized Pros & Cons equipment. Field experiences have shown that the exist- + Fast, hygienic and generally effective sludge removal ing designs for dense urban areas are limited in terms of + Efficient transport possible with large vacuum trucks their emptying effectiveness and travel speed, and their + Potential for local job creation and income genera- ability to negotiate slopes, poor roads and very narrow tion lanes. Moreover, demand and market constraints have + Provides an essential service to unsewered areas prevented them from becoming commercially viable. - Cannot pump thick, dried sludge (must be thinned Under favourable circumstances, small vehicles like the with water or manually removed) Vacutug are able to recover the operating and mainte- - Garbage in pits may block hose nance costs. However, the capital costs are still too high - Cannot completely empty deep pits due to limited to sustainably run a profitable business. suction lift Both the sanitation authority and private entrepreneurs - Very high capital costs; variable operating costs may operate vacuum trucks, although the price and lev- depending on use and maintenance el of service may vary significantly. Private operators - Hiring a vacuum truck may be unaffordable for poor may charge less than public ones, but may only afford households to do so if they do not discharge the sludge at a cer- - Not all parts and materials may be locally available tified facility. Private and municipal service providers - May have difficulties with access should work together to cover the whole faecal sludge management chain. References & Further Reading Boesch, A. and Schertenleib, R. (1985). Pit Emptying on-Site Health Aspects/Acceptance The use of a vacuum _ Excreta Disposal Systems. Field Tests with Mechanized truck presents a significant health improvement over Equipment in Gaborone (Botswana). International Reference manual emptying and helps to maintain the Collection Centre for Waste Disposal, Dübendorf, CH. and Storage technology. Still, truck operators are not Available at: www.sandec.ch always accepted by the community and may face diffi- (Comprehensive summary of technical components, perfor- culties with finding appropriate locations to dump the mance with different sludge types, and maintenance) collected sludge. _ Chowdhry, S. and Koné, D. (2012). Business Analysis of Fecal Sludge Management: Emptying and Transportation Operation & Maintenance Most pump trucks are Services in Africa and Asia. Bill & Melinda Gates Foundation, manufactured in North America, Asia or Europe. Thus, Seattle, US. in some regions it is difficult to locate spare parts and a Available at: www.susana.org/library mechanic to repair broken pumps or trucks. New trucks are very expensive and sometimes difficult to obtain. _ O’Riordan, M. (2009). Investigation into Methods of Pit Latrine Emptying. Management of Sludge Accumulation in VIP Therefore, older trucks are often used, but the savings Latrines. WRC Project 1745, Water Research Commission, are offset by the resulting high maintenance and fuel Pretoria, ZA. costs that can account for more than two thirds of the Available at: www.susana.org/library total costs incurred by a truck operator. Truck owners (Includes a detailed analysis of field experiences with the must be conscientious to save money for the purchase Vacutug) of expensive replacement parts, tires and equipment. The lack of preventive maintenance is often the cause _ Strande, L., Ronteltap, M. and Brdjanovic, D. (Eds.) (2014). Faecal Sludge Management. Systems Approach for Imple- for major repairs. mentation and Operation. IWA Publishing, London, UK. The addition of chemical additives for desludging is Available at: www.sandec.ch not recommended because they tend to corrode the (Detailed book compiling the current state of knowledge on sludge tank. all aspects related to FSM) Compendium of Sanitation Systems and Technologies Compendium of Sanitation Systems and Conveyance C: Functional Group 89.